Efforts to determine the etiological agents associated with multiple sclerosis have continued. We have completed the immunological studies using direct migration inhibition, lymphocyte cytotoxicity and complement mediated cytotoxic test and have concluded that there is no significant difference in the cellular immune response of MS patients and carefully matched controls. Flow cytofluorometric techniques to measure the cellular immune response of lymphocytes from a number of non-human primates have been completed. Correlation of T and B lymphocyte markers as detected by monoclonal antibodies have been initiated in human and non-human primate systems. Significant alterations in the response of non-human primate lymphocytes when treated with ammonium chloride to these monoclonal antibodies has been observed. Application of the ELISA technique to measure IgG and IgM against a variety of viruses has been completed. A rapid, viral antigen diagnostic technique which reduces the time necessary to identify herpes virus in clinical specimens from 3-7 days to 6-24 hours has been developed using the avidin-biotin system. Routine monitoring of tissue cultures from experimental viral studies from mycoplasma contamination and efforts to develop new techniques to monitor cultures for contamination have been continued.